Improvement in hollow augers



G. N. STEARNS. Hollow-Auger;

No. 203,384. Patented May 7,1878.

Illllll B 'llllllll lllllll bfl muuuull lllm1mm c T-ED TA PATENT QFFIGE.

GEORGE. n, STEABNS, on SYRACUSE, NEW YORK.

lMPROVlE M 5 1- HOLLOWAUGERS'Q Specification forming part of LettersPatent No. 203,384, dated May 7, 1878'; application filed June 15, 1876.

ting tenons of different sizes andlengths, and to obviate the necessityof using a separate auger for each sized tenon.'

My invention consists inp'roviding two jaws,

constructed, as herein after more specifically set forth, with a jointsimilar to a rule-joint, which forms a pivot or hinge." The pivoting"-pin, passing down through the face-rim'of the frame, secures the jaws tothe frame, which, together with a peculiarly-shaped V in one jaw and aconcave projection in the other, forms the adjusting devices fordetermining the diameter of the tenons to be cut, and also in-providinga combined shank for connecting the tool to a bit-stock, and a stock fordetermining the length of tenon.

The .construction is more fully set forth as follows, in which referenceis had to the annexed drawing, like letters indicating correspondingparts.

Figure l is a side view of the tool; Fig. 2, an end or face view,-withthe jaws closed; Fig. 3, the same with the jaws expanded. Fig. 4. showsthe jaws detached.

The letter A represents the body or frame of the auger, made of metal,preferably of malleable iron or brass, and 'consisting, as appears inthe drawing, of three, more orless, bars, joined at the rear end to ahub, through which the combined shank and stop a, having a graduatedscale upon one of its flat sides, passes. The hub is conical, anddivided into two or more sections by milling or sawing in with a toolprepared for this purpose. It is provided with a bindingmut, I), screwedonto it, by means of which it can be firmly affixed to the shank at anydesired point of its length. The shank, as will be readily observed,when released, can be set in or out to determine the length of tenon tobe cut.

I am aware that a shank and stop combined in one piece is not new, as Inow have a patent on this device; but the combination of the dividedtapering hub and binding-screw with theshank is new, and an importantfeature of my invention.

' On the front or cutter-head end of the frame or bodythe bars terminatein a circular ring of metal, its upper rim forming the bearing orfacerim, upon which the pivoted jaws are ope'rated, as mentioned before.At two points opposite to each other on the face-rim, and upon its lower'side,'two bosses are" cast on. These areperforated, so as to allow thepivoting-pin d, Fig. 2, to pass through thejaws and rim, and it issecurely held in place by a nut. The pinion P is also provided with abolt, having a thread on its lower end. This pinion works in a rack, rr, and its bolt projects down through the perforation in the face-rimand boss, and is set as required by the set-nut. The jaw B is providedwith a cutter, k, which is held in place and operated by a pivoted strapor cap, f, at or below the foot of the cutter k. The jaw has a concaveprojection, which forms a bearing for the jaw upon the timber of thespoke as it is cut away, aiding materially in centering and steadyingthe tool while cutting. The opposite or guide jaw is provided with .aV-shaped indenture of peculiar form, as shown" at Fig. 2, its officebeing to center the work properly. Many experiments on shaping thisindenture led me to adopt this as the only shape of the guide-j aw whichwould conform perfectly to the peripheries of the various tenons ofdifferent diameters in the scope of adjustment. Both jaws are providedwith the segments 1' 1", Figs. 2 and 3, the segment of the guide-jawoverlapping that of the cutter-carrying jaw. These segments are providedon opposite sides with a rack, the teeth of which are so graduated as toallow the pinion to gear into both. This I found necessary, in order tomake the tool center perfectly in each size. The pinion P is locatedopposite the pivot d, and gears into both racks on opposite sides, sothat by turning it the jaws are expanded or contracted to any desireddegree on each side of the center equally, so as to be at all timescentered on the axis of revolution. They are firmly held at any desiredsize by a bolt on the pinion-axis thatp'asses through the rim and bossof the frame, its lower end being provided with a thread, upon which aset-nut operates as a securing device.

It will be observed that, in consequence of the segment of the guide-jaw overlapping that of the cutter-carrying jaw, it is brought nearer tothe axis upon which the pinion revolves, and therefore when the pinionis turned its cogs engage the rack of the guide-jaw, moving it withgreater rapidity than the cutter-carrying jaw, which, by reason of theoverlap, is farther from the center of the axis of the pinion. Thenecessity for this will be obvious on examining Figs. 2 and 3. As thepeculiar shapes of the indenture in the guide-jaw and projection in thecutter-carrying jaw, if both moved alike, would bring the cutting centerof the auger on different sides of the axial center of the body andshank, and render the tool unsteady in use, the weight of metal in thejaws is distributed so as to balance when placed in a bit-stock or lathefor use. The tool is strong, compact, and durable.

Having thus fully described my invention, I claim.

. 1. The jaws B G pivoted at a point, d, in.

combination witheach other, and the cutterhead of a hollow auger,substantially as and for the purposes specified.

2. In combination with two jaws, pivoted at any point d on thecutter-head, of a hollow auger, the segments 1 r provided with rackshaving graduated teeth, and pinion P, operating to center the jawsautomatically at any degree of adjustment, and for the simultaneousopening and closing of the jaws, as herein set forth and specified.

3. The pinion 1?, provided with an axial pinpassing through a boss onthe frame of the cutter-head of a hollow auger, gearing into thesegmental rack r r of the expanding and contracting jaws, in combinationtherewith, and the auger-frame A, as herein set forth, and for thepurposes specified.

4. The projection c and recess or indenture V in the jaws, substantiallyas and for the purposes specified.

5. The adjusting divided hub and bindingscrew, in combination with eachother, and the combined gaging-shank and stop a, substantially asspecified.

In witness whereof I have hereto set my hand.

GEO. N. STEARNS. In presence of- P. B. MOLENNAN, J. J. GREENOUGH.

